Objective To establish an animal model of hand,foot,and mouth disease(HFMD)in Syrian hamsters coinfected with coxsackievirus A6(CVA6)and coxsackievirus B1(CVB1).Methods 42 Syrian hamsters were divided into a CVA6 infection group,CVB1 infection group,CVA6 and CVB1 coinfection group and control group.A HFMD model was established by nasal instillation of virus solution and phosphate-buffered saline.Clinical and physiological indicators and detoxification status were monitored and recorded for 15 d,and animals were selected on day 7(D7)after infection for histopathology and viral antigen and nucleic acid testing.Results Hamsters in the single-infection and coinfection groups showed clinical symptoms similar to human HFMD.White blood cell,neutrophil,and lymphocyte result were characteristic of viral infection.Both viral nucleic acids were detected in throat swabs,feces,blood,and tissues and both viruses were isolated from fecal samples.Pathological damage and positive co-localization of CVA6 and CVB1 viral antigen proteins and nucleic acids were found in brain and other tissues.Conclusions Nasal instillation of a CVA6 and CVB1 mixture can successfully coinfect Syrian hamsters,replicate herpes infection similar to human HFMD,and cause pathological viral myocarditis and encephalitis damage.The result showed that the coinfection group was more seriously affected than the single-infection group,with worse clinical symptoms,increased viral replication,and obvious tissue pathological damage.This study provides a reference for further basic and clinical research into human enterovirus coinfection.

Objective To observe the value of pool sign on T2WI for differentiating solitary brain metastasis(SBM)from solitary mass type high grade glioma(HGG).Methods Totally 120 patients with SBM(SBM group)and 184 patients with solitary mass type HGG(HGG group)confirmed by postoperative pathology or clinical follow-up were retrospectively enrolled.The incidence of pool sign were compared between groups,and the efficacy of pool sign for differentiating SBM from solitary mass type HGG was analyzed.Results Pool sign was noticed in 37 cases(37/120,30.83％)in SBM group and 9 cases(9/184,4.89％)in HGG group,the incidence of pool sign in SBM group was higher than that in HGG group(x2=38.063,P＜0.001).The sensitivity,specificity,positive predictive value and negative predictive value of pool sign for differentiating SBM and solitary mass type HGG was 30.83％(37/120),95.11％(175/184),80.43％(37/46)and 67.83％(175/258),respectively.In SBM group,the incidence of pool sign in cases with primary tumor of adenocarcinoma,squamous cell carcinoma and neuroendocrine carcinoma was 40.79％(31/76),16.67％(3/18)and 12.50％(3/24),respectively,with significant difference(x2=8.911,P=0.012),while compared pairwisely showed significant difference between SBM of adenocarcinoma and neuroendocrine carcinoma(x2=6.505,P=0.011).Conclusion The pool sign on T2WI was helpful for differentiating SBM,especially SBM of adenocarcinoma from solitary mass type HGG.

Objective:To review the clinicopathological features of TFE3-rearranged renal cell carcino-ma(TFE3-RCC)with venous tumor thrombus(VT)(TFE3-VT),to explore treatment strategies and to prognostic characteristics,and to provide diagnostic and therapeutic references for TFE3-VT patients.Methods:Patients who underwent surgery at Department of Urology,Peking University Third Hospital from January 2013 to January 2024 were enrolled,including three cohorts:Pathologically confirmed TFE3-VT patients,TFE3-RCC patients without VT(TFE3-non-VT),and non-TFE3-rearranged renal cell carcinoma patients with VT(non-TFE3-VT).Clinical history,imaging data,pathological data,and follow-up records were collected.Primary and secondary endpoints were progression-free survival(PFS)and overall survival(OS),respectively.(1)Baseline characteristics were compared between the TFE3-VT and TFE3-non-VT patients.Normally distributed continuous variables were expressed as mean±SD and compared using Student's t-test;non-normally distributed variables were expressed as M(P25,P75)and analyzed with Mann-Whitney U test;categorical variables were described as frequency and percentage[n(％)]and compared by x2 test or Fisher's exact test.(2)Clinical history,radiological presenta-tions,surgical data,and histopathological features of the TFE3-VT patients were comprehensively charac-terized.(3)Survival analysis was performed for the TFE3-VT patients.Follow-up data of the TFE3-VT patients were described in detail,and their survival outcomes were compared with the TFE3-non-VT and non-TFE3-VT patients.When compared with the TFE3-non-VT counterparts,Kaplan-Meier method was used to generate PFS and OS curves among:(1)the TFE3-RCC patients across clinical stages Ⅰ-Ⅳ;(2)TFE3-VT versus TFE3-non-VT cohorts;(3)stage Ⅲ subgroups of the TFE3-VT and TFE3-non-VT patients.Intergroup survival differences were statistically evaluated using Log-rank tests.For comparisons with the non-TFE3-VT patients,a 1∶1 propensity score matching(PSM)was implemented to balance baseline characteristics between the two cohorts.Post-matching Kaplan-Meier curves were generated to compare PFS and OS between the matched groups,with Log-rank tests employed to determine statistical significance of survival disparities.All statistical analyses were conducted with R software(v 4.2.3),and two-tailed P＜0.05 was considered statistically significant.Results:The study included 45 TFE3-RCC patients:13 TFE3-VT and 32 TFE3-non-VT cases.Additionally,523 non-TFE3-VT patients were enrolled.Among the 13 TFE3-VT patients,9 were female(69.2％)and 4 male(30.8％),with a mean age of(37.9±14.4)years,mean BMI of(22.2±3.5)kg/m2,median age-adjusted Charlson comorbidity index(aCCI)of 1.0(0.0,1.0),and preoperative creatinine level of(75.3±15.9)μmol/L;tumors were located in the left kidney in 7 patients(53.8％)and right kidney in 6(46.2％);preoperative distant metastasis(M1 stage)was present in 6 patients(46.2％),while 7(53.8％)showed no metastasis;VT distribution by Mayo level comprised 7 cases(53.8％)at level 0,1 case each at levels Ⅰ and Ⅳ(7.7％respectively),and 2 cases each at levels Ⅱ and Ⅲ(15.4％respectively);surgical approaches comprised open surgery(n=2,15.4％),laparoscopic surgery(n=6,46.1％),and robot-assisted laparoscopic surgery(n=5,38.5％);mean operative time was(273±79)min,and intraoperative blood loss was(722±570)mL;mean maximum tumor diameter was(10.8±2.4)cm.All the 13 patients underwent TFE3 protein immunohistochemistry(IHC)staining,with 7 confirmed by fluorescence in situ hybridization(FISH).Tumor recurrence or metastasis occurred in 11 patients(84.6％),and 9(69.2％)patients died during follow-up.Median PFS was 4 months(1 year PFS rate:31％),and median OS was 13 months(1 year OS rate:54％).Survival analysis of 45 TFE3-RCC pa-tients revealed statistically significant differences in PFS and OS across all the clinical stages(P＜0.001).The TFE3-VT patients exhibited significantly worse PFS and OS than the TFE3-non-VT patients(P＜0.001),with persistent significance in stage Ⅲ subgroup analysis(P＜0.05).After PSM,TFE3-VT pa-tients showed significantly inferior PFS compared with non-TFE3-VT(P=0.01),though no significant difference was shown between the OS curves(P=0.11).Conclusion:TFE3-VT predominantly occurs in young females with frequent preoperative metastases.Strongly-positive staining of TFE3 protein in IHC stai-ning and red-green split signals in FISH tests are reliable diagnostic markers.TFE3-VT patients exhibit in-ferior survival compared with TFE3-non-VT patients and earlier progression than non-TFE3-VT patients.

Objective:To review the clinicopathological features of TFE3-rearranged renal cell carcino-ma(TFE3-RCC)with venous tumor thrombus(VT)(TFE3-VT),to explore treatment strategies and to prognostic characteristics,and to provide diagnostic and therapeutic references for TFE3-VT patients.Methods:Patients who underwent surgery at Department of Urology,Peking University Third Hospital from January 2013 to January 2024 were enrolled,including three cohorts:Pathologically confirmed TFE3-VT patients,TFE3-RCC patients without VT(TFE3-non-VT),and non-TFE3-rearranged renal cell carcinoma patients with VT(non-TFE3-VT).Clinical history,imaging data,pathological data,and follow-up records were collected.Primary and secondary endpoints were progression-free survival(PFS)and overall survival(OS),respectively.(1)Baseline characteristics were compared between the TFE3-VT and TFE3-non-VT patients.Normally distributed continuous variables were expressed as mean±SD and compared using Student's t-test;non-normally distributed variables were expressed as M(P25,P75)and analyzed with Mann-Whitney U test;categorical variables were described as frequency and percentage[n(％)]and compared by x2 test or Fisher's exact test.(2)Clinical history,radiological presenta-tions,surgical data,and histopathological features of the TFE3-VT patients were comprehensively charac-terized.(3)Survival analysis was performed for the TFE3-VT patients.Follow-up data of the TFE3-VT patients were described in detail,and their survival outcomes were compared with the TFE3-non-VT and non-TFE3-VT patients.When compared with the TFE3-non-VT counterparts,Kaplan-Meier method was used to generate PFS and OS curves among:(1)the TFE3-RCC patients across clinical stages Ⅰ-Ⅳ;(2)TFE3-VT versus TFE3-non-VT cohorts;(3)stage Ⅲ subgroups of the TFE3-VT and TFE3-non-VT patients.Intergroup survival differences were statistically evaluated using Log-rank tests.For comparisons with the non-TFE3-VT patients,a 1∶1 propensity score matching(PSM)was implemented to balance baseline characteristics between the two cohorts.Post-matching Kaplan-Meier curves were generated to compare PFS and OS between the matched groups,with Log-rank tests employed to determine statistical significance of survival disparities.All statistical analyses were conducted with R software(v 4.2.3),and two-tailed P＜0.05 was considered statistically significant.Results:The study included 45 TFE3-RCC patients:13 TFE3-VT and 32 TFE3-non-VT cases.Additionally,523 non-TFE3-VT patients were enrolled.Among the 13 TFE3-VT patients,9 were female(69.2％)and 4 male(30.8％),with a mean age of(37.9±14.4)years,mean BMI of(22.2±3.5)kg/m2,median age-adjusted Charlson comorbidity index(aCCI)of 1.0(0.0,1.0),and preoperative creatinine level of(75.3±15.9)μmol/L;tumors were located in the left kidney in 7 patients(53.8％)and right kidney in 6(46.2％);preoperative distant metastasis(M1 stage)was present in 6 patients(46.2％),while 7(53.8％)showed no metastasis;VT distribution by Mayo level comprised 7 cases(53.8％)at level 0,1 case each at levels Ⅰ and Ⅳ(7.7％respectively),and 2 cases each at levels Ⅱ and Ⅲ(15.4％respectively);surgical approaches comprised open surgery(n=2,15.4％),laparoscopic surgery(n=6,46.1％),and robot-assisted laparoscopic surgery(n=5,38.5％);mean operative time was(273±79)min,and intraoperative blood loss was(722±570)mL;mean maximum tumor diameter was(10.8±2.4)cm.All the 13 patients underwent TFE3 protein immunohistochemistry(IHC)staining,with 7 confirmed by fluorescence in situ hybridization(FISH).Tumor recurrence or metastasis occurred in 11 patients(84.6％),and 9(69.2％)patients died during follow-up.Median PFS was 4 months(1 year PFS rate:31％),and median OS was 13 months(1 year OS rate:54％).Survival analysis of 45 TFE3-RCC pa-tients revealed statistically significant differences in PFS and OS across all the clinical stages(P＜0.001).The TFE3-VT patients exhibited significantly worse PFS and OS than the TFE3-non-VT patients(P＜0.001),with persistent significance in stage Ⅲ subgroup analysis(P＜0.05).After PSM,TFE3-VT pa-tients showed significantly inferior PFS compared with non-TFE3-VT(P=0.01),though no significant difference was shown between the OS curves(P=0.11).Conclusion:TFE3-VT predominantly occurs in young females with frequent preoperative metastases.Strongly-positive staining of TFE3 protein in IHC stai-ning and red-green split signals in FISH tests are reliable diagnostic markers.TFE3-VT patients exhibit in-ferior survival compared with TFE3-non-VT patients and earlier progression than non-TFE3-VT patients.

Objective To observe the value of pool sign on T2WI for differentiating solitary brain metastasis(SBM)from solitary mass type high grade glioma(HGG).Methods Totally 120 patients with SBM(SBM group)and 184 patients with solitary mass type HGG(HGG group)confirmed by postoperative pathology or clinical follow-up were retrospectively enrolled.The incidence of pool sign were compared between groups,and the efficacy of pool sign for differentiating SBM from solitary mass type HGG was analyzed.Results Pool sign was noticed in 37 cases(37/120,30.83％)in SBM group and 9 cases(9/184,4.89％)in HGG group,the incidence of pool sign in SBM group was higher than that in HGG group(x2=38.063,P＜0.001).The sensitivity,specificity,positive predictive value and negative predictive value of pool sign for differentiating SBM and solitary mass type HGG was 30.83％(37/120),95.11％(175/184),80.43％(37/46)and 67.83％(175/258),respectively.In SBM group,the incidence of pool sign in cases with primary tumor of adenocarcinoma,squamous cell carcinoma and neuroendocrine carcinoma was 40.79％(31/76),16.67％(3/18)and 12.50％(3/24),respectively,with significant difference(x2=8.911,P=0.012),while compared pairwisely showed significant difference between SBM of adenocarcinoma and neuroendocrine carcinoma(x2=6.505,P=0.011).Conclusion The pool sign on T2WI was helpful for differentiating SBM,especially SBM of adenocarcinoma from solitary mass type HGG.

Objective To establish an animal model of hand,foot,and mouth disease(HFMD)in Syrian hamsters coinfected with coxsackievirus A6(CVA6)and coxsackievirus B1(CVB1).Methods 42 Syrian hamsters were divided into a CVA6 infection group,CVB1 infection group,CVA6 and CVB1 coinfection group and control group.A HFMD model was established by nasal instillation of virus solution and phosphate-buffered saline.Clinical and physiological indicators and detoxification status were monitored and recorded for 15 d,and animals were selected on day 7(D7)after infection for histopathology and viral antigen and nucleic acid testing.Results Hamsters in the single-infection and coinfection groups showed clinical symptoms similar to human HFMD.White blood cell,neutrophil,and lymphocyte result were characteristic of viral infection.Both viral nucleic acids were detected in throat swabs,feces,blood,and tissues and both viruses were isolated from fecal samples.Pathological damage and positive co-localization of CVA6 and CVB1 viral antigen proteins and nucleic acids were found in brain and other tissues.Conclusions Nasal instillation of a CVA6 and CVB1 mixture can successfully coinfect Syrian hamsters,replicate herpes infection similar to human HFMD,and cause pathological viral myocarditis and encephalitis damage.The result showed that the coinfection group was more seriously affected than the single-infection group,with worse clinical symptoms,increased viral replication,and obvious tissue pathological damage.This study provides a reference for further basic and clinical research into human enterovirus coinfection.

Objective:To explore the interaction effects on brain activity between the smoking addiction and weight status by resting-state functional magnetic resonance imaging.Methods:Retrospective analysis of clinical data and resting-state functional magnetic resonance imaging data were analyzed from 99 recruited subjects from January 2019 to December 2021. All participants were divided into four groups: overweight smokers ( n=24), normal-weight smokers ( n=28), overweight non-smokers ( n=19), and normal weight non-smokers ( n=28). Calculate regional homogeneity (ReHo) to reflect the internal brain activity of the subjects. Two-way ANOVA was used to detect the interaction effects between smoking addiction and overweight on ReHo by SPM12 software, correcting for age, years of education and head motion. Results:The interaction effect between smoking addiction and overweight on ReHo was significant in right superior frontal gyrus(x, y, z=15, 9, 60)(GRF corrected, Pvoxel<0.005, Pcluster<0.05). The ReHo value in the right superior frontal gyrus of overweight smokers was significantly higher than that of normal weight smokers ( t=3.768, P<0.001, Bonferroni corrected). The ReHo values in the right superior frontal gyrus of overweight non-smokers were significantly lower than those of normal weight non-smokers ( t=-3.242, P=0.002, Bonferroni corrected). The ReHo values in the right superior frontal gyurs of normal-weight smokers were significantly lower than those of normal weight non-smokers( t=-3.540, P=0.001, Bonferroni corrected). The ReHo values in the right superior frontal gyrus of overweight smokers were significantly higher than those of overweight non-smokers ( t=3.392, P=0.002, Bonferroni corrected). Correlation analyses showed that the strengthen ReHo value in right superior frontal gyrus was positively associated with pack-year in smoking addicts( r=0.387, P=0.007, Bonferroni corrected). Conclusion:Smoking addiction and overweight have an antagonistic effect on brain activity in the right superior frontal gyrus, which may provide potential therapeutic targets for individuals with comorbidity of smoking addiction and overweight.

Objective:To determine the optimal irradiation energy and frequency for the establishment of melasma mouse model using simple ultraviolet irradiation, and to provide guidance on animal strains and irradiation protocols for the successful establishment of melasma model.Methods:Animal models of melasma were established using BALB/c female mice and C57BL/6JNifdc female mice. BALB/c female mice were divided into 4 groups using a simple randomization method: A, B, C and G, with 5 mice in each group. C57BL/6JNifdc female mice were divided into 4 groups: D, E, F and H, with 5 mice in each group. All mice were irradiated with 8.428 mW/cm 2 of ultraviolet light. The irradiation time was 15 s (single irradiation energy of 0.13 J/cm 2) in groups A and D, 15 min (single irradiation energy of 7.59 J/cm 2) in groups B and E, and 30 min (single irradiation energy of 15.17 J/cm 2) in groups C and F. Each cycle consisted of 5 consecutive days of irradiation followed by 2 days of cessation, totaling 4 cycles of irradiation. Groups G and H were not irradiated. At the end of irradiation, all mice were kept under normal conditions. One week later, 3 mice from each group were selected for HE, Masson-Fontana, Masson, and immunohistochemical staining. Quantitative analysis was performed to measure the thickness of the acanthocyte layer, melanin granules, collagen percentage, and interleukin-1 (IL-1) levels. The remaining mice were kept for an additional week, depilated and photographed to observe the changes in coloration. Data were analyzed using SPSS 27.0 software, measurement data that did not conform to normal distribution were represented by M( Q1, Q3) and comparisons between groups were made using the Kruskal-Wallis rank sum test. Results:During the entire irradiation process, no visible discoloration was observed in the BALB/c female mice in all groups. In contrast, varying sizes of discoloration appeared in the C57BL/6JNifdc female mice in groups D, E, and F after irradiation in the second week. However, by the third week, the discoloration in group D gradually disappeared, while the discoloration in group E was more obvious than before. At the same time, group F exhibited significant discoloration, with some mice exhibited signs of skin peeling, burning and breakage on their backs. After the 4th week of irradiation, no new discoloration was formed in group D. The discoloration was more obvious in group E, and most mice in group F showed skin burn breakage. Two weeks after the completion of irradiation, there was no obvious discoloration on the dorsal skin of BALB/c female mice in all groups. In C57BL/6JNifdc female mice, group D showed no obvious discoloration, group E exhibited lighter discoloration compared to the 4th week post-irradiation, and group F had crusted skin at the burn sites with lighter discoloration than before. However, the discoloration in groups E and F was still obviously visible to the naked eye. HE staining showed that the difference in the thickness of the echinocyte layer was not statistically significant in groups A, B, C, and G ( H=1.08, P=0.782); whereas the difference was statistically significant in groups D, E, F and H ( H=12.85, P=0.005). The thickness of the echinocyte layer decreased gradually with the extension of the irradiation time. Additionally, there was a disruption in the arrangement of epidermal spindles in group F, and this situation was not observed in groups D and E. Masson-Fontana staining revealed no significant pigmentation in any of the BALB/c female mice. The difference in melanin granule counts between groups A, B, C, and G was not statistically significant ( H=7.77, P=0.051). In contrast, C57BL/6JNifdc female mice exhibited more noticeable pigmentation in the epidermis and dermis in groups E and F. The difference in melanin particle counts among groups D, E, F and H was statistically significant ( H=17.61, P<0.001), with melanin deposition increasing gradually with the duration of irradiation. Masson staining showed that the difference in collagen percentage between groups A, B, C, and G was not statistically significant ( H=7.26, P=0.064). However, significant disorganization of fibers and a loose structure were observed in groups E and F. The difference in collagen percentage between groups D, E, F, and H was statistically significant ( H=8.65, P=0.034). Immunohistochemical results showed that the difference in IL-1 expression levels between groups A, B, C, and G was statistically significant ( H=17.86, P<0.001); also between groups D, E, F, and H was statistically significant ( H=14.19, P=0.003), suggesting that ultraviolet irradiation stimulated an inflammatory response in the skin of mice. Conclusion:BALB/c female mice are not suitable for melasma models under the frequency and duration of irradiation in this experiment. C57BL/6JNifdc female mice are irradiated with a single irradiation energy dose of 7.59 J/cm 2 five days a week for 4 weeks, which can establish stable animal models of melasma with a specific level of pigmentation that persisted for at least 2 weeks.

Objective:To determine the optimal irradiation energy and frequency for the establishment of melasma mouse model using simple ultraviolet irradiation, and to provide guidance on animal strains and irradiation protocols for the successful establishment of melasma model.Methods:Animal models of melasma were established using BALB/c female mice and C57BL/6JNifdc female mice. BALB/c female mice were divided into 4 groups using a simple randomization method: A, B, C and G, with 5 mice in each group. C57BL/6JNifdc female mice were divided into 4 groups: D, E, F and H, with 5 mice in each group. All mice were irradiated with 8.428 mW/cm 2 of ultraviolet light. The irradiation time was 15 s (single irradiation energy of 0.13 J/cm 2) in groups A and D, 15 min (single irradiation energy of 7.59 J/cm 2) in groups B and E, and 30 min (single irradiation energy of 15.17 J/cm 2) in groups C and F. Each cycle consisted of 5 consecutive days of irradiation followed by 2 days of cessation, totaling 4 cycles of irradiation. Groups G and H were not irradiated. At the end of irradiation, all mice were kept under normal conditions. One week later, 3 mice from each group were selected for HE, Masson-Fontana, Masson, and immunohistochemical staining. Quantitative analysis was performed to measure the thickness of the acanthocyte layer, melanin granules, collagen percentage, and interleukin-1 (IL-1) levels. The remaining mice were kept for an additional week, depilated and photographed to observe the changes in coloration. Data were analyzed using SPSS 27.0 software, measurement data that did not conform to normal distribution were represented by M( Q1, Q3) and comparisons between groups were made using the Kruskal-Wallis rank sum test. Results:During the entire irradiation process, no visible discoloration was observed in the BALB/c female mice in all groups. In contrast, varying sizes of discoloration appeared in the C57BL/6JNifdc female mice in groups D, E, and F after irradiation in the second week. However, by the third week, the discoloration in group D gradually disappeared, while the discoloration in group E was more obvious than before. At the same time, group F exhibited significant discoloration, with some mice exhibited signs of skin peeling, burning and breakage on their backs. After the 4th week of irradiation, no new discoloration was formed in group D. The discoloration was more obvious in group E, and most mice in group F showed skin burn breakage. Two weeks after the completion of irradiation, there was no obvious discoloration on the dorsal skin of BALB/c female mice in all groups. In C57BL/6JNifdc female mice, group D showed no obvious discoloration, group E exhibited lighter discoloration compared to the 4th week post-irradiation, and group F had crusted skin at the burn sites with lighter discoloration than before. However, the discoloration in groups E and F was still obviously visible to the naked eye. HE staining showed that the difference in the thickness of the echinocyte layer was not statistically significant in groups A, B, C, and G ( H=1.08, P=0.782); whereas the difference was statistically significant in groups D, E, F and H ( H=12.85, P=0.005). The thickness of the echinocyte layer decreased gradually with the extension of the irradiation time. Additionally, there was a disruption in the arrangement of epidermal spindles in group F, and this situation was not observed in groups D and E. Masson-Fontana staining revealed no significant pigmentation in any of the BALB/c female mice. The difference in melanin granule counts between groups A, B, C, and G was not statistically significant ( H=7.77, P=0.051). In contrast, C57BL/6JNifdc female mice exhibited more noticeable pigmentation in the epidermis and dermis in groups E and F. The difference in melanin particle counts among groups D, E, F and H was statistically significant ( H=17.61, P<0.001), with melanin deposition increasing gradually with the duration of irradiation. Masson staining showed that the difference in collagen percentage between groups A, B, C, and G was not statistically significant ( H=7.26, P=0.064). However, significant disorganization of fibers and a loose structure were observed in groups E and F. The difference in collagen percentage between groups D, E, F, and H was statistically significant ( H=8.65, P=0.034). Immunohistochemical results showed that the difference in IL-1 expression levels between groups A, B, C, and G was statistically significant ( H=17.86, P<0.001); also between groups D, E, F, and H was statistically significant ( H=14.19, P=0.003), suggesting that ultraviolet irradiation stimulated an inflammatory response in the skin of mice. Conclusion:BALB/c female mice are not suitable for melasma models under the frequency and duration of irradiation in this experiment. C57BL/6JNifdc female mice are irradiated with a single irradiation energy dose of 7.59 J/cm 2 five days a week for 4 weeks, which can establish stable animal models of melasma with a specific level of pigmentation that persisted for at least 2 weeks.

Objective To explore the automated identification and diameter measurement methods for inferior vena cava (IVC) based on clinical ultrasound images of IVC. Methods An automated identification and localization method based on topology and automatic tracking algorithm was proposed. Tracking algorithm was used for identifying and continuously locating to improve the efficiency and accuracy of measurement. Tests were conducted on 18 sets of ultrasound data collected from 18 patients in intensive care unit (ICU),with clinicians' measurements as the gold standard. Results The recognition accuracy of the automated method was 94.44％ (17/18),and the measurement error of IVC diameter was within the range of±1.96s (s was the standard deviation). The automated method could replace the manual method. Conclusion The proposed IVC automated identification and localization algorithm based on topology and automatic tracking algorithm has high recognition success rate and IVC diameter measurement accuracy. It can assist clinicians in identifying and locating IVC,so as to improve the accuracy of IVC measurement.